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A WW2 device for breaking the M-209 encryption machine
Get PDFAccording to an eyewitness report by German engineer Reinold Weber published in 2004, a German cryptanalysis unit broke the U.S. cipher machine M-209 in the Second World War. For this purpose, the specialists involved built an electromechanical machine (“Weber machine”), which included binary logic and bore some resemblance with the Turing Bombe. In previously unpublished documents contained in the TICOM reports, information can be found about a cryptanalysis device that is probably identical with the Weber machine. Based on the said sources, this paper describes what is known about this deciphering technology
Scherbius and the Enigma. Political, Economic and Military Conditions
Get PDFIn 1917, the German War Ministry commissioned Arthur Scherbius to invent a cipher machine. The early history of the device was determined by political and economic disasters. The Enigma was taken up by dubious businessmen in 1920. In 1925 that ended in a catastrophe
Extending a Multicopter Analysis Tool using Modelica and FMI for Integrated eVTOL Aerodynamic and Electrical Drivetrain Design
Get PDFThis paper describes how the Functional Mock-up Interface (FMI) standard for model-based systems engineering can be used to expand the capabilities of aerodynamic multicopter analysis tools to perform integrated design of electric vertical take-off and landing (eVTOL) systems. The proposed eVTOL system, which consists of a drivetrain and battery, was developed using Modelica and exported to MATLAB/SIMULINK using model exchange to interact with a domain-specific tool specializing in calculating the aerodynamics of the aircraft. This shows the value of FMI to extend the capabilities of tools for multicopter aerodynamic analysis to design eVTOL using integrated multi-domain system simulation
Enhancing SSP creation using sspgen
Get PDFThe System Structure and Parameterization (SSP) standard is a tool independent standard to define complete systems consisting of one or more components, including its parameterization, that can be transferred between simulation tools. Thus the SSP standard is a natural extension to the Functional Mock-up Interface (FMI) standard, allowing systems of components, rather than just individual components, to be simulated in a growing number of supported tools. This paper introduces sspgen, a textual Domain Specific Language (DSL) for generating SSP archives. The aim of the DSL is to greatly simplify the creation of SSP compatible simulation systems. sspgen is written in the Kotlin programming language, which provide syntax highlighting and static code analysis in selected tools, full access to Java compatible libraries, and more importantly a scripting context so that sspgen definitions can be easily shared and executed on demand. As the DSL is based on a generic programming language, it enables complex expressions to be evaluated for the purpose of e.g., pre-simulation and initialization of variables. The DSL also performs validation and through integration with the Open Simulation Standard - Interface Specification (OSP-IS) even allows more complex connections to be formed than the single scalar connections that the SSP standard defines, while still retaining compliance. Furthermore, the DSL handles automatic packaging of its referenced content into a ready-to-use SSP archive. As a whole, the introduced package makes it easier to create, modify and share SSP systems
Performance Enhancements for Zero-Flow Simulation of Vapor Compression Cycles
Get PDFModels that correctly describe the dynamic behavior of vapor compression cycle at low or zero refrigerant mass flow rates are valuable because they can be used to handle low load, on/off cycling and inactive component conditions. However, low- or zero-flow simulation imposes significant computational challenges because of high frequency oscillations in mass flow. We explore techniques that may be used for improving robustness and performance of low- or zero-flow simulation. Comparisons are conducted to demonstrate the efficacy of the proposed techniques. It is shown that these techniques can result in simulations that are more robustand significantly faster than real-time
Material Production Process Modeling with Automated Modelica Models from IBM Rational Rhapsody
Get PDFThis paper describes a method to author dynamic simulation models in Modelica from a manufacturing architectural model structure in SysML. Modelica models are generated from IBM Rational Rhapsody and simulated using Modelon Impact. Following a brief overview of the overall modeling approach and tool coupling, the Modelica modeling is detailed for computing process throughput and processing time. Following the model overview, a sample application for the production of the pharmaceutical ingredient atropine is demonstrated
Understanding and Improving Model Performance at Small Mass Flow Rates in Fluid System Models
Get PDFThis paper provides a detailed analysis of the reasons behind the poor simulation performance observed when mass flow rates become very small, commonly referred to as zero mass flow issues. By using simple example models, we effectively demonstrate the underlying causes of these simulation performance issues. We highlight various contributing factors that play a significant role in exacerbating the problem. Furthermore, we propose and examine countermeasures to mitigate these challenges. These countermeasures include modifications to the model itself, utilization of available settings in simulation tools, and adjustments to the solver. By implementing and evaluating these countermeasures, we illustrate their impact on improving simulation performance in scenarios involving low mass flow rates
Presentation, Validation and Application of the EnergyProcess Library
Get PDFGreen production of hydrogen and its derivatives is becoming a cornerstone of industry decarbonation. Apart from the technological development point of view, optimizing the overall production chains dynamically is essential for the competitiveness of these systems. In this paper, we describe how we built, validated and used a Modelica-based library dedicated to the simulation and optimization of energy process for the production of green molecules. Especially, models of complex media, salt cavity hydrogen storage and electrolysis module are presented. An example application shows that the models of the library are particularly handy for the modeling of a 5MW electrolysis module, which is used for the calibration of an optimization model
Design proposal of a standardized Base Modelica language
Get PDFThis paper is presenting the design proposal of a simplified version of the Modelica language. Base Modelica is designed to serve as an intermediate representation enabling a clean separation of front-end and back-end matters when processing a Modelica model. Furthermore, is it intended as a basis to restructure the Modelica Language Specification considering two parts: the basic features and the advanced language constructs. After discussing the motivation, solution approach, and risks, the paper is highlighting a selection of design choices that have been made for the current pre-release version of the language. Code examples are given to illustrate and highlight various aspects of the language. Open issues, conclusions, and an outlook finalize the paper. By attracting more tool vendors and researchers to work with this intermediate representation the whole Modelica community is expected to benefit from new utilities to inspect, analyze, optimize and process equations-based models in general and Modelica models in particular
NTNU-TRH system at the MultiGED-2023 Shared on Multilingual Grammatical Error Detection
Get PDFThe paper presents a monolithic approach to grammatical error detection, which uses one model for all languages, in contrast to the individual approach, which creates separate models for each language. For both approaches, pre-trained embeddings are the only external knowledge sources. Two sets of embeddings (Flair and BERT) are compared as well as two approaches to the problem of multilingual rammar detection, building individual and monolithic systems for multilingual grammar error detection. The system submitted to the test phase of the MultiGED-2023 shared task ranked 5th of 6 systems. In the subsequent open phase, more experiments were conducted, improving results. These results show the individual models to perform better than the monolithic ones and BERT embeddings working better than Flair embeddings for the individual models, while the picture is more mixed for the monolithic models